Apparatus for sensing combustible gases of differing densities

ABSTRACT

A system for sensing the presence of a combustible gas mixture, whether caused by a heavier-than-air or lighter-than-air combustible gas, including a vertical chimney having its bottom near the floor of a room and its top near the ceiling, and intermediate parts, with a timer-controlled heater for causing an intermittent updraft and a combustible gas sensor near the top of the chimney: a chimney with intermediate ports.

United States Patent m1 3,744,289

Lown July 10, 1973 [54] APPARATUS FOR SENSING COMBUSTIBLE 3,476,517 11/1969 Smith 23/255 E CASES OF DIFFERING DENSITIES 2,727,203 12/1955 Zeitlin et a1. 340/237 S 2,185,361 1/1940 Towne 340/237 S [75] In ento E ls Lown, Mllltown. 2,317,024 4/1943 Bliss 340/237 s Assignee: Aured Charles, Mmmwn, NJ. 3 3,041,591 6/1962 Moore 340/237 R part interest FOREIGN PATENTS OR APPLICATIONS I 22 d Sept. 24 1971 699,466 11/1940 Germany 340/237 PP N05 183,549 A Primary Examiner-James J. Gil] Attorney-Charles H. Recht [52] US. Cl. 73/23, 73/42115 R 51 Int. Cl. com 1/26 1 1 ABSTRACT [58] Field of Search 73/23, 24, 25, 26, A system for sensing the presence of a combustible gas 73/27, 29, 421.5 R; 23/232 R, 232 E, 230 L, mixture, whether caused by a heavier-than-air or 254 R, 254 E, 255 R, 255 E; 340/237 R, 237 lighter-than-air combustible gas, including a vertical S; 250/43.5 R, 43.5 D, 43.5 MR; 356/201, chimney having its bottom near the floor of a room and 207; 417/207; 137/13; 98/45, 58 its top near the ceiling, and intermediate parts, with a timer-controlled heater for causing an intermittent up- [56] References Cited draft and a combustible gas sensor near the top of the UNITED STATES PATENTS chimney: a chimney with intermediate ports.

2,644,934 7/1953 Grant 73/4215 R X 7 Claims, 1 Drawing Figure CEILING PAINIEBJUHOBT5 3,744,289

. INVENTOR v ELLSWORTH H LOWN ATTORNEY APPARATUS FOR SENSING COMBUSTIBLE GASES OF DIFFERING DENSITIES BACKGROUND OF THE INVENTION The present invention relates to apparatus for sensing combustible gas mixtures.

It has long been recognized that leakage of combustible gas constitutes a serious safety hazard. To overcome this hazard, various devices have been provided to sense the presence of a combustible gas mixture and to provide an output which was utilized for sounding an alarm and/or for closing a valve in a gas main. Such organization have been known for use in connection with the detection of leakage of heating gas in a home or other building, and for shutting off the heating gas main upon sensing a combustible gas mixture. Such devices have also been used in mines, where combustible gas leakage has been found to be an ever-present danger.

Typically, the combustible gas mixture sensors or detectors heretofore known have comprised one or more resistance elements, the resistance or other electrical characteristics of which was changed upon the occurrence of a combustible gas mixture in the presence of the element. However, the devices heretofore provided have been capable of detecting or sensing the presence of a gas of only a particular density, and have only been capable of sensing combustible gas mixtures caused by gases which were either heavier-than-air or lighterthan-air.

Many homes are heated by conventional heating gas, supplied by a Public Service Utility through underground mains, leading into the home, and to the furnace within the home. Such furnaces may be located either in a furnace room at ground level, or in a furnace room located in a basement. Such gas, should a leakage occur, either through the above mentioned equipment or through exterior leakage, is known to be lighterthan-air, and will therefore accumulate near the ceiling, forming there a combustible gas mixture which is subject to ignition and explosion.

In addition to the above unwanted source of spurious leakage of heating gas, it has been found that many home occupants choose to store gasoline in or near the furnace room, attached garage or occasionally some other liquid. In either case, there is danger of spillage of the liquid, so that upon evaporation thereof, gasoline fumes or other combustible fumes are created. Also, containers of such liquids may be inadvertently left unsealed, so that over a period of time there is evaporation of the liquid, and the danger of the accumulation of fumes in such an amount as to constitute an explosive mixture. Gasoline and other fumes, as noted, are heavier-than-air. Hence, in some situations there is a danger of combustible mixtures being present of different gas densities, some heavier-thanair and some lighter-than-air.

SUMMARY OF THE INVENTION Apparatus is provided for sensing the presence of combustible vapors or combustible gas mixtures, whether heavier-than-air or lighter-than-air and comprises a chimney-like conduit open at its upper and lower ends. The lower end is adjacent the floor of a room or other chamber, and the upper end is adjacent the ceiling, the conduit extending generally vertically. In or adjacent to the upper end of the conduit is a combustible gas sensor of known construction, which is preferably of an electrical nature and having electrical outputs for generating a suitable signal when combustible gas is detected. The conduit may have a plurality of axially spaced ports therein so that gas from the environment can flow into the conduit from differing levels between the floor and ceiling. Associated with the conduit is a device for causing a flow of gaseous medium upwardly through the conduit; preferably, this is in the form of an enclosed electrical heater, which is intermittently energized by a suitable timer device. The output of the gas sensor is connected to a gas heating main valve and/or alarm dircuit. When the timer device energizes the sensor and the heater, the sensor will thereupon sample the atmosphere relatively close to the ceiling, to thereby effect detection of a combustible mixture which is lighter-than-air; after a short period of time, the heater will have attained a suitable temperature and will then heat the surrounding atmosphere to cause a flow of gaseous medium upwardly from the lower end to the upper end of the conduit, so that the ,gas sensor can then detect the presence of heavierthan-air combustible mixtures.

Among the objects of the present invention is the provision of apparatus for sensing a combustible mixture whether that mixture is heavier-than-air or lighterthan-air. Another object is to provide apparatus for sensing combustible gas mixtures of differing densities. Yet another object of the present invention is the provision of such a gas sensor apparatus which is of economical construction, and which requires a minimum amount of relatively expensive electrical equipment.

Other objects will be apparent from a consideration of the following description and claims.

BRIEF DESCRIPTION OF THE DRAWING The single FIGURE is a partially schematic view of the present invention apparatus, with parts broken away.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is shown a gas detector apparatus generally designated 10, and comprising a chimney-like conduit 12 which is located in a room, such as a furnace room in a home. The chimneylike conduit 12 will be seen to have its open lower end 14 supported somewhat above and adjacent to a floor, as by legs 20, 22. The open upper end 16 is adjacent the ceiling of the room, and there are provided in the conduit intermediate axially-spaced inlet ports 18A, 18B, etc., these intermediate inlet ports being spaced so as to admit gaseous medium of different densities into the interior of the conduit 12.

Adjacent the open lower end 14 is an electric heater 24 suitably supported beneath the open end or passage 14 by brackets 26. The electric heater 24 is schematically shown in the drawing, but will be understood to be a suitably encased heater which will not cause ignition of any combustible mixture present in the environment of the lower end 14 of conduit 12. An enclosed resistance heater or light bulb may be utilized. Heater 24 is connected by conductors 28 to a switch 30, and thence to lines L-l and L-2. Switch 30 is of any suitable construction, and is controlled by a timer 32, which is also connected to the lines L-l and L-2. As will be understood, timer 32 will close the switch 30 for a suitable interval of time, during weich the heater 24 will be energized, and will also open switch 30 at intervening intervals of time, during which no current will be supplied to the heater 24. 7

In or adjacent the upper end of passage 16 of the chimney-like conduit 12 there is provided a gas sensor 40 of known construction, gas sensor 40 being supported by a suitable bracket 42, and connected with conductors 28 by conductors 44. Gas sensor 40 has an electrical output in the form of conductors 46, which are connected with analarm circuit 48 and an electrically controlled gas main valve 50.

In operation, when the switch 30, governed by the timer 32, is closed, there will initially be no significant upward flow of gaseous medium through the open inlet or passage 14 of the chimney-like conduit 12. During such time, the atmosphere adjacent the ceiling will communicate with the gas sensor 40, through one or more of the passages or ports 18A, 188, etc., where present, and if not present, past the upper end of the conduit 12. Should this atmosphere be a combustible gas mixture, which may have been caused by leakage of the heating gas flowing through the valve 50 to the furnace of the structure in which the apparatus is located, the gas sensor 40 will generate an electric output which will be supplied to the alarm circuit 48, to thereby sound an alarm, and which will also be supplied to the valve 50, to close it. Thus, the further flow of heating gas into the structure or building will be prevented.

After a period of time, the energization of heater 24 will cause a flow of gaseous medium upwardly through the chimney-like conduit 12, thereby carrying to the gas sensor 40 a sample of the gaseous medium which is adjacent the floor, entering through the inlet passage or opening 14. If this gaseous medium, which is of relatively higher density and therefore somewhat heavierthan-air is combustible in nature, containing for example gasoline fumes, then the gas sensor 40 will be actuated as above noted, with consequent actuation of alarm circuit 48 as well as valve 50.

While reference has been made hereinabove to leakage of heating gas supplied by Public Service Utilities, it will be understood that the present invention is equally usable where the heating medium is propane gas, or the like, stored in a suitable container in or adjacent the home.

There has been provided an apparatus for sensing the presence of combustible vapors or gas in a home, hospital, school, nursing home, public building or the like,

whether those vapors were gas heavier-than-air or lighter-than-air. Either type of gaseous combustible mixture is capable of being sensed by the herein disclosed apparatus, with resultant automatic safety precautions being effected, whether they be the sounding of an alarm, or the closing of a valve. The apparatus herein provided is extremely economical, and readily installed, requiring a minimum of expensive electrical equipment. Further, the disclosed apparatus will operate to sense gases of different densities reliably over a long period of time, requiring a minimum amount of maintenance and replacement of parts.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

I claim:

1. Apparatus for sensing the presence of combustible vapors in a room having a floor and ceiling comprising:

a conduit having its lower end adjacent the floor and its upper end adjacent the ceiling, passage means at the ends of said conduit, means for causing a flow of gaseous medium through said conduit from one end to the other thereof,

means positioned adjacent the passage means to which the gaseous medium flows for sensing explosive character of said gaseous medium,

and means for intermittently energizing said flow causing means.

2. The apparatus of claim 1, said last mentioned means comprising a timer.

3. The apparatus of claim 1, said flow causing means comprising an electric heater.

4. The apparatus of claim 3, said electric heater being positioned adjacent the lower end of said conduit.

5. The apparatus of claim 1, said sensing means comprising electric output means, and electrically energized valve means connected to said electric output means.

6. The apparatus of claim 1, and further including intermediate passage means comprising at least one port in said conduit intermediate the ends thereof.

7. The apparatus of claim 1, and further including intermediate passage means comprising a plurality of axi ally spaced ports in said conduit intermediate the ends thereof. 

1. Apparatus for sensing the presence of combustible vapors in a room having a floor and ceiling comprising: a conduit having its lower end adjacent the floor and its upper end adjacent the ceiling, passage means at the ends of said conduit, means for causing a flow of gaseous medium through said conduit from one end to the other thereof, means positioned adjacent the passage means to which the gaseous medium flows for sensing explosive character of said gaseous medium, and means for intermittently energizing said flow causing means.
 2. The apparatus of claim 1, said last mentioned means comprising a timer.
 3. The apparatus of claim 1, said flow causing means comprising an electric heater.
 4. The apparatus of claim 3, said electric heater being positioned adjacent the lower end of said conduit.
 5. The apparatus of claim 1, said sensing means comprising electric output means, and electrically energized valve means connected to said electric output means.
 6. The apparatus of claim 1, and further including intermediate passage means comprising at least one port in said conduit intermediate the ends thereof.
 7. The apparatus of claim 1, and further including intermediate passage means comprising a plurality of axially spaced ports in said conduit intermediate the ends thereof. 